Combined directional and impact drilling motor
A directional drilling mechanism is disclosed. The mechanism is also an impact drill.
This invention relates generally to directional drilling, and more specifically to directional drilling with air hammer drilling tools or non impact drill bits used in air drilling.
BACKGROUND OF THE INVENTIONCurrently, underground directional drilling has been largely limited to drilling with roller cone or polycrystalline diamond compound (PDC) type bits with mud or air-mist rotary drilling motors utilizing rotor-stator or similar technologies. These technologies use liquid based drilling fluids. Large portions of the drilling industry use air hammer drilling tools also known as drill hammers for conventional straight-hole drilling that strictly use air as the drilling medium. However, rotor-stator technology is not suitable or too expensive for air hammer drilling tools. Consequently, the air hammer drilling industry has had limited access to the benefits of directional drilling.
SUMMARY OF THE INVENTIONIt is an object of the present invention to provide an underground directional drilling mechanism that allows standard air hammer drilling tools to be utilized in the directional drilling process by the rotating a drill hammer during the impact process without rotating the drill string. These and other objects and advantages of the invention will become readily apparent as the following description is read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Before explaining the disclosed embodiment of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
The present invention uses standard air hammer drilling tools and utilizes them in the directional drilling process. Existing hammer tools can be used without modification. In addition, the present invention generates enough torque to use conventional drill bits in some applications. The present invention achieves this by operating a drilling motor rotation device that uses compressed air from an above-ground compressor to rotate down-hole percussive or hammer drills in oil and gas well drilling, or other down-hole drilling applications.
As will be shown in more detail below, the present invention incorporates a commercially available vane-type pneumatic air motor, a planetary gear box including a single-piece stem pinion gear made from hardened steel, and multiple universal joints, among other features. The entire device is attached to the bottom of the drill-string (thus below-ground).
The present invention performs directional drilling by rotating a down-hole percussive hammer drill without rotating the cylinder housing or drill string. It also uses an air driven motor mounted within the device that receives power from above-ground air compressor. It also has sealed tapered roller bearings used for centering the drive shaft and shouldering thrust and radial loads on the device.
One advantage of the present invention is that it can utilize any of a variety of commonly available air hammers. It is also an advantage of the present invention to not rotate the entire drill string along with the hammer. The present invention has bypass tubes for delivering excess compressed air not used by the vane motor to the hammer drill for its operation. The present invention also has check valves that send exhausted air from the vane motor to the well-bore.
The function of the hammer drill 600 is to pulverize rock with repeated linear blows. The drill string 100 simultaneously imparts rotation to the hammer 600 so that the buttons 604 on the hammer 600 do not repeatedly strike the rock surface in the same place. The hammer buttons 604 act as mini chisels. The cutting of the rock or other underground material takes place under the buttons 604. If the buttons 604 do not move (rotate), zero or minimal cutting takes place.
The drill string 100 rotates the entire hammer drill 600 in rotations per minute similar to rotations supplied by the drilling rig and drill string. This allows the buttons 604 to rotate across the entire face of the borehole and thus cut the entire face. Additionally, the drill string 100 supplies sufficient torque to overcome the drag on the hammer 600 from the sides of the borehole that hamper rotation.
Since the motor 300 supplies the rotation of the hammer 600, the exterior of the drill string 100 itself need not rotate. This allows for the bend in the middle of the bent sub assembly 400 so as to impart a direction to the drilling action. As shown in
For the present invention to achieve maximum effectiveness and convenience, the rotary power source must use the same power source as the linear power source for the air hammer 600. Having two separate power sources is not cost-effective, and is also more difficult to implement. In an exemplary embodiment, the motor assembly 300 uses compressed air, although the present invention should not be considered as limited exclusively thereto.
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The regulator 386 ensures that a specific, fixed amount of air at a constant pressure arrives at the motor 304. Meanwhile, the air filter 380 preserves the motor 304. The filter 380 removes all coarse material typically found in compressed air streams found on drilling rigs.
The motor 304 must be small enough to fit inside the tube of the motor assembly 300, and also allow space for tubing 311 to be placed alongside the motor 304. As shown in
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The top gear hub and the gear hub base (
The gearbox housing 314 is comprised of the internal gear and two end plates. The gearbox housing remains fixed because it is attached to the wall of the outside shell of the housing 324 by housing screws 308. The planet gear assembly rotates inside the cavity of the gearbox housing. As shown in
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The drive shaft 510 is centered within the bearing housing 524 by means of tapered roller bearings 512. Accordingly,
The bottom assembly 500 further serves to transfer air flow channeled through the bent sub assembly 400 to the hammer 600. The hammer 600 obtains all of its non-rotational longitudinal hammering force from high pressure air flow. This air flow is sent through the interior aperture of the drive shaft 510 to the hammer.
The drive shaft 510 and box coupling 5050 is secured within the bottom assembly 500 by means of retaining rings. Accordingly, a retainer piece assembly 800 fits as shown in
It is important to understand how various portions of the drill string 100 rotate, while others do not. The planet gears 316 and sun pinion 312 as well as keyed shaft 334 rotate, while the threaded housings 324, 424, and 524 remain fixed. Additionally, the drive shaft 510, tapered roller bearings 512, coupling 505, shear pins 504, and drive shaft 520 all rotate.
A cross section of the motor assembly 300 is shown in
A perspective view of the retainer assembly is shown in
The present invention is configured to allow for the compressed air not utilized by the vane motor 304 to bypass that motor and instead flow through the device to the air hammer 600. To achieve this bypass, the drill string 100 of the present invention has bypass tubes 311 that direct compressed air from the chamber that houses the filter past the chamber that houses the regulator 324 and vane motor 304 to a chamber housing the sun gear 312 and pinion gear 316.
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It is an advantage of the present invention that it allows for a drilling process that requires minimal torque. Thus the connections within the drill string 100 can be made up with tools typically found on drilling rigs. No high torque tools are needed.
It is anticipated that various changes may be made in the arrangement and operation of the system of the present invention without departing from the spirit and scope of the invention, as defined by the following claims.
Claims
1. A directional and rotating drill mechanism, comprising:
- an air compressor, for providing pneumatic energy to said mechanism;
- a motor assembly, for rotatably driving a hammer which in turn rotatably contacts a wellbore area to be drilled, wherein said motor assembly uses pneumatic energy provided by said air compressor;
- a bent sub assembly, connected to motor assembly; for controllably providing change in direction of said drill; and
- a bottom assembly, connected to said bent sub assembly, for linearly driving and controlling said hammer, wherein said bottom assembly uses pneumatic energy provided by said air compressor;
- wherein said motor, bent sub, and bottom assemblies are connected together in a drill string.
2. The mechanism of claim 1, further comprising:
- said hammer having buttons positioned on its surface;
- said hammer reciprocates within a portion of said bottom assembly so as to contact said area with repeated linear blows, wherein said mechanism simultaneously imparts rotation to said hammer so that said buttons on the hammer do not repeatedly strike the same area of said wellbore.
3. The mechanism of claim 1, further comprising:
- said drill string is controlled from above ground using a drill pipe.
4. The mechanism of claim 1, further comprising:
- said drill string rotates the entire hammer drill in rotations per minute similar to rotations supplied by the drilling rig and drill pipe, the buttons to rotate across the entire face of said borehole.
5. The mechanism of claim 1, further comprising:
- said drill string is supplied sufficient torque energy by said air compressor to overcome the drag on the hammer from the sides of the borehole that hamper rotation.
6. The mechanism of claim 1, further comprising:
- a motor inside said motor assembly is sufficiently small to fit inside the tube of the drill string.
7. The mechanism of claim 1, further comprising:
- said motor, bent sub, and bottom assemblies are joined using threaded connectors.
8. The mechanism of claim 1, further comprising:
- said joining occurs using sufficient torque so as to keep the drill string from disassembling during use.
9. The mechanism of claim 1, further comprising:
- said drill string can withstand tensional forces encountered during the drilling process.
10. The mechanism of claim 7, further comprising:
- said connectors provide a tight seal for routing the air necessary to drive the hammer.
11. The mechanism of claim 1, further comprising:
- an auxiliary compressor to assists said air compressor.
12. The mechanism of claim 1, wherein said bottom assembly further comprises:
- a regulator to limit the air pressure of the compressed air before it gets to the vane motor.
13. The mechanism of claim 6, further comprising:
- an air regulator, connected between said air compressor and said motor, so that the air pressure from said compressor is regulated so as to not overdrive said motor, yet still provides optimum pressure for said motor to function.
14. The mechanism of claim 6, further comprising:
- said motor has fins that turn like the blades of a fan or turbine.
15. The mechanism of claim 1, further comprising:
- motor assembly has check valves which are the ports where the air is exhausted out from said vane motor to the well bore.
16. The mechanism of claim 15, further comprising:
- said check valves keep fluids and cuttings from entering the interior of said drill string when air is not being exhausted.
17. The mechanism of claim 15, further comprising:
- said check valves are one-way so as to prevent drilled materials from flowing back into said drill string.
18. The mechanism of claim 13, further comprising:
- said regulator ensures that a specific, fixed amount of pressure arrives at the motor.
19. The mechanism of claim 13, further comprising:
- an air filter, connected between said compressor and said regulator, for preserving said motor.
20. The mechanism of claim 19, further comprising:
- said filter removes all coarse material typically found in compressed air streams found on drilling rigs.
21. The mechanism of claim 6, further comprising:
- motor must be small enough to fit inside the tube of the motor assembly, and also allow space for air tubing to be placed alongside the motor.
22. The mechanism of claim 21, further comprising:
- said tubing allows a supply of air from said air compressor to be not directed at the motor and instead be supplied to said hammer.
23. The mechanism of claim 1, further comprising:
- said motor assembly contains threaded plugs for lubrication.
24. The mechanism of claim 1, further comprising:
- a gear system for transforming pneumatic energy into rotational; located within said motor assembly.
25. The mechanism of claim 24, wherein said gear system further comprises:
- a planetary gear system having a sun pinion gear at its center, surrounded by planet gears; and
- a top gear hub and a gear hub base hold the planet gears in place with the proper alignment, so that they have optimum contact with the sun pinion gear.
26. The mechanism of claim 1, wherein said bent sub assembly further comprises:
- two universal joints which act as two different independent links with another shaft in between the two so that they turn smoothly.
27. The mechanism of claim 26, further comprising:
- said bent sub assembly can be built with a specific angle bend, measured in degrees.
28. The mechanism of claim 27, further comprising:
- said bent or sloped area can be built with a variety of slopes or bends.
29. The mechanism of claim 1, further comprising:
- a bearing supported drive shaft to a box coupling for which said hammer can be attached;
- wherein said drive shaft is attached to said threaded housing using shaft pins.
30. The mechanism of claim 29, further comprising:
- a plurality of pins secure the box to bearing supported drive shaft under normal and occasionally high tension loads.
31. The mechanism of claim 30, further comprising:
- a plurality of keyways and keys are placed perpendicular to said pins to impart torque from the drive shaft to the box.
32. The mechanism of claim 1, further comprising:
- an optional stabilizer, located within said bottom assembly, which keeps said drill string centered in the wellbore and keeps side load off said hammer.
33. The mechanism of claim 29, further comprising:
- said drive shaft is centered within the bearing housing by means of tapered roller bearings.
34. The mechanism of claim 29, further comprising:
- said box coupling transfers thrust loads from the hammer to a plurality of tapered roller bearings, which can withstand take both axial and radial loads.
35. The mechanism of claim 29, further comprising:
- said drive shaft and box coupling is secured within the bottom assembly by means of retaining rings.
36. The mechanism of claim 22, further comprising:
- motor assembly has flutes cut laterally along its length to allow for said tubing containing bypass air to reach the bent sub assembly.
37. A method of performing directional drilling, comprising:
- providing pneumatic power to a drill string using a single power source;
- applying a hammer attached to said drill string within a well shaft in a linear path using said pneumatic power; and
- simultaneously rotating said hammer using said pneumatic power.
Type: Application
Filed: Dec 16, 2005
Publication Date: Jun 21, 2007
Inventors: Michael Sanders (Lexington, KY), Jerry Foster (Richmond, KY), Duane Bennett (Brookside, KY)
Application Number: 11/305,607
International Classification: E21B 7/04 (20060101);